from Wiktionary, Creative Commons Attribution/Share-Alike License

n. that being which is oneself

from the GNU version of the Collaborative International Dictionary of English

pro. I or me in person; -- used for emphasis, my own self or person; as I myself will do it; I have done it myself; -- used also instead of me, as the object of the first person of a reflexive verb, without emphasis.

from The Century Dictionary and Cyclopedia

An emphatic or reflexive form of the first personal pronoun I or me, either nominative or (as originally) objective.

Etymologies

Middle English mi-self, from Old English mē selfum, mē selfne : mē, me; see me-1 in Indo-European roots + selfum, selfne, dative and accusative of self, self; see self.

(American Heritage® Dictionary of the English Language, Fourth Edition)

But it does mean that when I can no longer protect my own interests, when my affairs depend upon others far more than on myself -- a condition in which we all occasionally find ourselves -- I am not to _fret myself_, not to churn my spirit into nameless fears.

Henceforward alone and cruelly distrustful of myself, I then took up sides — not without anger — _against myself_ and _for_ all that which hurt me and fell hard upon me; and thus I found the road to that courageous pessimism which is the opposite of all idealistic falsehood, and which, as it seems to me, is also the road to _me_ — _to my mission_.

To say now that I never can forget; that I feel myself bound to you as one human being cannot be more bound to another; -- and that you are more to me at this moment than all the rest of the world; is only to say in new words that it would be a wrong against _myself_, to seem to risk your happiness and abuse your generosity.

After the court had heard the evidence of myself and Mr. Davis, Mr. Jekyl made a most eloquent appeal to the jury, a _common not_ a SPECIAL jury: he called some witnesses to their character, but no one appearing, _I offered myself_ to give three of them, who had been my father's servants, a character for sobriety and industry, with which the court and counsel appeared much pleased.